src/lib-roff/iftoa.c

   1 /*@
   2  * Copyright (c) 2014 - 2017 Steffen (Daode) Nurpmeso <steffen@sdaoden.eu>.
   3  *
   4  * Copyright (C) 1989 - 1992, 2000, 2004
   5  *    Free Software Foundation, Inc.
   6  *      Written by James Clark (jjc@jclark.com)
   7  *
   8  * This is free software; you can redistribute it and/or modify it under
   9  * the terms of the GNU General Public License as published by the Free
  10  * Software Foundation; either version 2, or (at your option) any later
  11  * version.
  12  *
  13  * This is distributed in the hope that it will be useful, but WITHOUT ANY
  14  * WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16  * for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with groff; see the file COPYING.  If not, write to the Free Software
  20  * Foundation, 51 Franklin St - Fifth Floor, Boston, MA 02110-1301, USA.
  21  */
  22
  23 #include "config.h"
  24
  25 #include "lib.h"
  26
  27 #define INT_DIGITS 19           /* enough for 64-bit integer FIXME lib.h */
  28
  29 char *if_to_a(int i, int decimal_point)
  30 {
  31   /* room for a -, INT_DIGITS digits, a decimal point, and a terminating '\0' */
  32   static char buf[INT_DIGITS + 3];
  33   char *p = buf + INT_DIGITS + 2;
  34   int point = 0;
  35   buf[INT_DIGITS + 2] = '\0';
  36   /* assert(decimal_point <= INT_DIGITS); */
  37   if (i >= 0) {
  38     do {
  39       *--p = '0' + (i % 10);
  40       i /= 10;
  41       if (++point == decimal_point)
  42         *--p = '.';
  43     } while (i != 0 || point < decimal_point);
  44   }
  45   else {                        /* i < 0 */
  46     do {
  47       *--p = '0' - (i % 10);
  48       i /= 10;
  49       if (++point == decimal_point)
  50         *--p = '.';
  51     } while (i != 0 || point < decimal_point);
  52     *--p = '-';
  53   }
  54   if (decimal_point > 0) {
  55     char *q;
  56     /* there must be a dot, so this will terminate */
  57     for (q = buf + INT_DIGITS + 2; q[-1] == '0'; --q)
  58       ;
  59     if (q[-1] == '.') {
  60       if (q - 1 == p) {
  61         q[-1] = '0';
  62         q[0] = '\0';
  63       }
  64       else
  65         q[-1] = '\0';
  66     }
  67     else
  68       *q = '\0';
  69   }
  70   return p;
  71 }
  72
  73 // s-it2-mode